The idea came up during a conversation in the office. A colleague at the IT company where I work mentioned a story he'd seen about a failed attempt to fly using helium balloons. I said it had to be possible – that with enough of them I could make the chair I was sitting in fly. It was a typical Friday afternoon conversation and no one took it very seriously. But the idea stuck with me and kept nagging.

So I bought a few balloons – nothing unusual, just the big ones that are often used at displays and promotions – to see if I could get the chair to take off. With rigging, it took five balloons to get it airborne. That was a point of no going back – I knew the next step had to be to fly in the chair myself.

As children, I think, most of us imagine holding a balloon on a string and drifting away. It crosses cultures and borders, but we're told it's impossible. I enrolled at a flight school to become licensed to fly hot-air and gas balloons. Then I worked out how many balloons I'd need, designed the rigging and safety harness. I did all the physics on paper, built models, and a year later was ready to make the inaugural flight.

That flight took place in June 2008. Strapped into my office chair under a canopy of 55 balloons, I covered more than 50 miles in four hours, climbing to an altitude of nearly 15,000ft. Last April, I broke the world record for the longest free-floating balloon flight – a 14-hour journey across North Carolina. The record wasn't my goal. Really, I wanted to prove to myself that crossing the English Channel was within my grasp.

I had to give it a shot. Of course, approaching the Civil Aviation Authority to register a cluster of balloons as an aircraft isn't easy. Then there was insurance, airworthiness inspections and so on, which took a lot of time and paperwork.

The night before the flight, in May last year, I was very afraid. The balloons had to be inflated at night, so I could take off at sunrise when the wind is calmest. There's something about the dead of night that adds to the feeling of dread. I'm not a reckless adventurer and had planned scrupulously for the right weather, but once airborne I could rely only on myself, minute to minute. The flight began 10 miles inland at a gliding club in Ashford. At 5am, I simply floated away, gradually climbing over the Kent countryside. After all the work and the waiting, it was a relief to be free of the earth.

By sheer luck, I hit the coast right at the white cliffs of Dover. As I drifted out over open water, the chair turned by chance through 360 degrees, giving me a spectacular view of the cliffs and the land receding as it did so.

This form of flight is the only one that's truly silent. There are no jets, no rotors – with a hot-air balloon you have the sound of the flame, and even in a glider you hear the wind rushing past. Hanging from helium balloons, you're moving with the wind. You don't feel it on your skin – it's incredibly peaceful.

England was behind me, the cold waters of the channel lay below and it was 41 miles to the continent. There were about a hundred potential problems I'd had to consider and prepare for. Boats and ships were few and far between, and I knew that sudden immersion in the cold water could kill me in minutes – I'd rejected the idea of using a wet suit to keep the weight down.

Yet the sheer joy of the adventure outweighed any fear. At the start of the journey, I had to call air traffic control in London on my radio to open my flight plan – the delight of being able to announce, "London, this is gas balloon November 878 Uniform Papa" cannot be underestimated.

Descending from 7,000ft, I approached France, passing right over the lighthouse at Dunkirk. The bad news was, I was heading for the Belgian border, and I didn't have permission to land there. Ahead of me were two radio towers – potentially deadly, as their guy wires can slice clean through the balloons. Needing to reach the ground quickly, I cut off a whole tier of my balloons and landed with a single bounce in a field full of lettuces.

The entire journey lasted three hours and 22 minutes. Compared with the exhaustive preparation, it was nothing, but the feeling of accomplishment will last a lifetime.